This invention relates generally to paper wound tubes, more specifically to an elongated paper tube, and method of making the same, having supportive end rings that seat in rabbets formed within each end of the tube so that the outside and inside diameters of the paper tube, are uniform, end-to-end, including the support rings.
Elongated paper tubes are known to the art. Such tubes are generally spirally or convolutely wound. Generally, such tubes are used to support a variety of materials depending upon the length and relative strength of the tube. For example, lightweight paper products, such as toilet paper and paper towels, are wound around relatively short, small diameter, lightweight paper tubes. These tubes are designed for single use and are discarded when the paper product is exhausted.
Heavier gauge tubes generally are used to wind yarn or cloth, or for holding heavy items such as carpeting. These tubes must have a smooth finish and uniform outside diameter to allow even winding and to prevent snagging of delicate materials wrapped about the tube. Furthermore, heavy-duty paper tubes are employed in the carpet industry to hold a roll of carpet. These large tubes are usually supported on mandrels so that the product can be loaded onto the tube or removed from the tube.
The heavy gauge, long tubes are relatively expensive to manufacture. Therefore, it is advantageous to form a heavy-duty paper tube that can be reused rather than discarded, and yet retain structural integrity. For the most part, the span of the paper tube covered by product stays intact and is reusable. However, the open ends of the tubes, especially the ends which extend out from under the material loaded thereon, can be damaged, rendering the tubes unusable after one application. Moreover, support or protective means applied to the ends of the tubes generally result in an end of a tube that has a greater or lesser inside or outside diameter, at the ends, than the inside or outside diameter of the body of the paper tube to which the end supports are attached. This results in an uneven wrapping or winding of a product on the paper tube. Furthermore, if the inside diameter of the ends of the paper tube is different from the inside diameter of the paper tube itself, the paper tube does not function as well on a mandrel.